• Bulletin of the Korean Chemical Society
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• v.6 no.2
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• pp.99-102
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• 1985

Substituent effects of substrate and nucleophile for the reaction of substituted phenacyl tosylates with pyridines were determined conductometrically in acetonitrile. Activation parameters for these reactions were also calculated. The substituent effects in nucleophile were increased with electron-donating power of pyridines and Br${\o}$nsted linear relationship was shown. Rate constant was increased by both electron-donating and electron-attracting groups in the substrate. It seems that dissociative S$_{N}$2 ("loose" transition state) mechanism is operating in the case of electron-donating substituents while associative S$_{N}$2 ("tight" transition state) mechanism is operative in the case of electron-attracting substituents.

• Journal of the Korean Chemical Society
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• v.67 no.3
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• pp.175-180
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• 2023

Tetra-aryl substituted A4-type porphyrins (TP, TD, TA) and trans-A2B2 porphyrins (DDP1, AAP1) with electron-donating or withdrawing groups were synthesized. The band gap energy of those porphyrins was calculated from their UV-Vis spectra and CV data. With an electron-withdrawing group, the band gap energy of porphyrin TA increased via the LUMO energy up. Meanwhile, the introduction of an electron-donating group decreased the band gap of porphyrin by HOMO level up as as in the case of porphyrin TD. The band gap (2.19-2.28 eV) of metalloporphyrin PP-Ni was greater than those (1.81-2.06 eV) of non-metalloporphyrins PP due to the LUMO level up.

• The Korean Journal of Food And Nutrition
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• v.33 no.5
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• pp.561-569
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• 2020

In this study, the antioxidative activity of Jeolpyun containing S. glauca (Bunge) Bunge powder (2%, 4%, 6%, and 8%) and extract (2%, 4%, 6%, and 8%) was evaluated based on the total polyphenol contents, electron-donating ability, scavenging of superoxide anion radical, and decomposition of hydrogen peroxide. Total polyphenol contents of Jeolpyun containing 8% S. glauca (Bunge) Bunge powder were the highest with a value of 2,280±0.00 ㎍ GAE/mL. It was observed that total polyphenol content exhibited a significant relation with concentrations at p<0.05. The electron-donating ability of Jeolpyun containing 8% S. glauca (Bunge) Bunge extract was the highest with a value of 83.93±0.69%. The electron-donating abilities revealed significant differences between concentrations (p<0.05). The superoxide radical scavenging ability of the blank was 0.01523±0.00068 and Jeolpyun containing 6% S. glauca (Bunge) Bunge powder was the highest with a value of 0.00977±0.00842. The hydrogen peroxide decomposing ability of Jeolpyun containing 0% S. glauca (Bunge) Bunge powder was -0.00377±0.0049; 8% S. glauca (Bunge) Bunge powder revealed the highest decomposing ability of -0.0476±0.0234. Hydrogen peroxide decomposing abilities revealed significant differences between concentrations (p<0.05). Jeolpyun containing S. glauca (Bunge) Bunge powder and extract demonstrated improved antioxidative activities.

• The Korean Journal of Food And Nutrition
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• v.35 no.4
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• pp.259-267
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• 2022

The purpose of this study was to evaluate the antioxidative activities of jeolpyun containing Cnidium officinale M extract (2%, 4%, 6%, 8%) by total polyphenol contents, electron donating ability on 2,2-diphenyl-1-picrylhydrazyl (DPPH), scavenging ability of superoxide anion radical and decomposing ability of hydrogen peroxide. In chromaticity analysis, the brightness significantly decreased with increasing Cnidium officinale M extract content. Jeolpyun containing 8% Cnidium officinale M extract revealing the highest value for the redness and the yellowness, 1.07, 12.70, respectively. The total polyphenol contents of jeolpyun containing 8% Cnidium officinale M extract were the highest content of 4,213 ㎍ gallic acid equivalent (GAE)/mL. The total polyphenol contents revealed significant difference (p<0.05). Jeolpyun containing 8% Cnidium officinale M extract revealing the highest electron donating ability (83.55%). The electron donating abilities were significantly related at p<0.05. The scavenging abilities of superoxide anion radical for jeolpyun containing 4% Cnidium officinale M extract revealed the highest ability (0.01676). There was no significant difference. The hydrogen peroxide decomposing ability for jeolpyun containing 8% Cnidium officinale M extract revealed the most hydrogen peroxide decomposing ability (-0.193) and the hydrogen peroxide decomposing ability revealed a significant difference (p<0.05).

• The Korean Journal of Food And Nutrition
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• v.30 no.6
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• pp.1286-1291
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• 2017

In this study, Pyracantha angustifolia (Franch.) C. K. Schneid was extracted with 70% methanol at room temperature for 48 hrs and concentrated under reduced pressure to measure its total polyphenol contents; furthermore, the effect of electron donating ability was examined. Methylene chloride, ethyl acetate, and methanol were used to fractionate the extract to testify total polyphenol contents, electron donating abilities, the removal abilities of superoxide radical as well as hydrogen peroxide. The total polyphenol contents were $2007.30{\pm}109.28{\mu}g\;GAE/mL$ in 70% methanol extract, $273.39{\pm}10.19{\mu}g\;GAE/mL$ in methylene chloride fraction, $80.57{\pm}0.64{\mu}g\;GAE/mL$ in ethyl acetate fraction, and $1,160.87{\pm}44.71{\mu}g\;GAE/mL$ in methanol fraction. The total polyphenol contents showed significant differences (p<0.05) between the solvents. The electron donating ability was $79.07{\pm}7.31%$ for 70% methanol extract, $22.34{\pm}0.64%$ for methylene chloride fraction, $5.33{\pm}0.28%$ for ethyl acetate fraction, and $32.26{\pm}1.10%$ for methanol fraction. The electron donating abilities were significantly different(p<0.05) between the solvents. The removal ability of superoxide radical was $0.018{\pm}0.003$ for 70% methanol extract, $0.007{\pm}0.002$ for methylene chloride fraction, $0.0147{\pm}0.003$ for ethyl acetate fraction, and nothing for methanol fraction. The measurement of hydrogen peroxide decomposition was $0.022{\pm}0.0046$ for 70% methanol extract, $0.0027{\pm}0.0015$ for methylene chloride fraction, $0.0037{\pm}0.0012$ for ethyl acetate fraction, and $0.0009{\pm}0.0001$ for methanol fraction.

• The Korean Journal of Food And Nutrition
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• v.32 no.6
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• pp.581-588
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• 2019

In this study, S. glauca (Bunge) Bunge extract was testified total polyphenol contents, electron donating ability on DPPH, and scavenging ability of superoxide anion radical and hydrogen peroxide. Total polyphenol contents of S. glauca (Bunge) Bunge extract were 7,053.30±915.93 ㎍ GAE/mL. In the fractions, fraction by ethanol was the highest content of 10,973.30±1,000.24 ㎍ GAE/mL. Fractions of ethyl acetate and water were 2,386.70±166.53 ㎍ GAE/mL, 2,413.30±41.63 ㎍ GAE/mL respectively. It was shown that total content of polyphenol according to solvent was significant relation at p<0.05. In the experiment of the electron donating ability, 70% ethanol extract and methylene chloride fraction were -246.15±24.17%, -254.01± 16.54% respectively. In case of ethyl acetate fraction, it was the highest electron donating ability to DPPH radical, 39.06±0.34%, and then water fraction of 36.71±5.55%, ethanol fraction of 29.77±2.57%, gradually. Electron donating abilities revealed significant difference (p<0.05) between the solvents. The superoxide radical scavenging ability of standard material was 0.029±0.0011; 70% ethanol extract of 0.022±0.00052, methylene chloride fraction of 0.027±0.00031, ethyl acetate fraction of 0.024±0.0011, ethanol fraction of 0.021±0.00024 and water fraction of 0.024±0.00019. Hydrogen peroxide scavenging ability of 70% ethanol extract was -0.0029±0.00040 and the others were as follow; methylene chloride fraction (-0.0042±0.00058), ethyl acetate fraction (-0.003± 0.0041), ethanol fraction (-0.0029±0.0015) and water fraction (-0.0028±0.00090).

• The Korean Journal of Food And Nutrition
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• v.31 no.4
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• pp.543-548
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• 2018

This study was conducted to investigated the antioxidant activities of extract for Megmoondong fruit. Liriope platyphylla L. was extracted with 70% methanol at room temperature for 48 hr and concentrated under reduced pressure to measure its total polyphenol contents and electron donating ability. The total polyphenol contents were $7,253.50{\pm}335.43{\mu}g\;GAE/mL$ in 70% methanol extract, $1,239.77{\pm}9.30{\mu}g\;GAE/mL$ in methylene chloride fraction, $919.30{\pm}50.83{\mu}g\;GAE/mL$ in methanol fraction, $105.44{\pm}2.04{\mu}g\;GAE/mL$ in ethyl acetate fraction. The total polyphenol contents showed significant differences (p<0.05) between the solvents. The electron donating ability was $69.17{\pm}12.61%$ for 70% methanol extract, $33.11{\pm}1.77%$ for methylene chloride fraction, $5.19{\pm}2.59%$ for ethyl acetate fraction, and $20.16{\pm}1.04%$ for methanol fraction. The electron donating abilities were significantly different (p<0.05) between the solvents. The removal ability of superoxide radical was $0.0174{\pm}0.0007$ for 70% methanol extract, $0.0164{\pm}0.0007$ for methylene chloride fraction, $0.0172{\pm}0.0007$ for ethyl acetate fraction, and nothing for methanol fraction. The measurement of hydrogen peroxide decomposition was $0.0985{\pm}0.1021$ for 70% methanol extract, $0.0896{\pm}0.0893$ for methylene chloride fraction, $0.0115{\pm}0.0085$ for ethyl acetate fraction, and $0.0170{\pm}0.0180$ for methanol fraction. The Liriope platyphylla L. extracts obtained from methylene chloride showed significantly relevant results in the total polyphenol contents and electron donating ability, which was higher than the original extract.

• Journal of the East Asian Society of Dietary Life
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• v.15 no.4
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• pp.419-430
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• 2005

In this study, to prove the effect of soybeans's electron donating ability and its addition on eel gouem, storage and sensory characteristics were examined. During the storage period, pH values of all gouem samples were decreased with initial increase except the control. BSB $3\%$ sample had the lowest pH value and YSB $10\%$ sample was the highest 6.71 in pH value at first storage day. The electron donating ability of soybeans were increased with the amount of addition. The electron donating ability of SBSB 20g sample was the highest, which was 2 ${\~}$ 3 times higher than that of YSB sample. L values of all the gouem samples had a tendency to decrease according to the storage period and amount of addition. All samples' a values were increased throughout the storage period, while b values decreased except the control and GNG sample. TBA and VBN values of all the samples were up and down throughout the storage period SBSB $10\%$ sample had the lowest in TBA value. The electron donating ability of all soybean samples and TBA value of eel gouem samples showed a negative correlation. Total plate count of bacteria was increased rapidly for initial storage period, but all samples showed a tendency of slow growth after the 8th day of storage. During all storage days, SBSB, BSB samples had a similar tendency of low total plate count growth. GNG $10\%$ sample showed the lowest in total plate count of bacteria at sixteenth day of storage. Sensory scores of all samples decreased with storage. For all the items of the sensory evaluation, SBSB $5\%$ sample got the highest score among all eel gouem samples. GNGSB sample showed the lowest in TBA value and total plate count of bacteria. And in the sensory evaluation, GNGSB sample got the highest scores for several items.

• Journal of the Korean Applied Science and Technology
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• v.33 no.4
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• pp.693-697
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• 2016

In this study, the electron donating ability(EDA) and total polyphenol content of herbal wine were examined. The herbal wine was obtained from extract concentration to evaluate its functional properties. The herbal wine were screened for their potential antioxidant activities using test such as electron donating ability(EDA) and total polyphenol content. The electron donating ability(EDA) were $21.81{\pm}0.56$ in herbal wine 15% and $40.45{\pm}1.60$ in herbal wine 35%. As the extract concentration was increased the electron donating ability(EDA) were significantly increased(p<0.05). The total polyphenol contents were measures $113.89{\pm}1.79{\mu}g\;GAE/m{\ell}$ in herbal wine 15%, $274.24{\pm}0.71{\mu}g\;GAE/m{\ell}$ in herbal wine 35%. As the extract concentration was increased the total polyphenol contents were significantly increased(p<0.05). Also, the total polyphenol contents were measures $61.75{\mu}g\;GAE/m{\ell}$ in herbal wine, the higher.

• Food Science and Preservation
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• v.9 no.4
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• pp.385-390
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• 2002

Functional activities of Lyophyllum ulmarium microwave-assisted extracts under different conditions including electron donating ability, tyrosinase inhibition activity and nitrite scavenging effect were examined. Total polyphenol content increased as increasing microwave power up to 90 W in the water extracts. Electron donating ability increased with microwave power up to 90 W in 50% ethanol extract and 99% ethanol extract. Tyrosinase inhibition activity and nitrite scavenging effect in the extract increased as microwave power increased during extraction. Total polyphenol content increased as extending extraction time up to 5 min in the water extract. But the highest electron donating ability and tyrosinase inhibition activity was obtained after 10 min extraction. Significantly higher total polyphenol content and electron donating ability were found in the water extract whereas greater tyrosinase inhibition activity and nitrite scavenging effect were observed in 99% ethanol extract. The maxium nitrite scavenging effect was found at pH 1.2 and decreased as pH increased.